Varying effects of temperature, Ca2+ and cytochalasin on fusion activity mediated by human immunodeficiency virus type 1 and type 2 glycoproteins

[摘要]

We examined fusion mediated by the human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) envelope glycoproteins under various experimental conditions. Incubation of HeLa cells expressing HIV-2_ROD and HIV-2_SBL/ISY envelope glycoproteins with HeLa-CD4 target cells resulted in fusion at temperatures ≥25°C whereas fusion with cells expressing HIV-1_Lai occurred only at ≥31°C. HIV-2 envelope glycoprotein-mediated fusion proceeded in the absence of Ca²⁺ in the culture medium, whereas HIV-1 fusion required Ca²⁺ ions for fusion. In contrast to HIV-2 envelope glycoprotein fusion, incubations in the presence of the 0.5 μM cytochalasin B completely inhibited HIV-1 envelope glycoprotein-mediated fusion. Our results suggest that in contrast to HIV-2, HIV-1 fusion is dependent on dynamic processes in the target membrane.

[学科分类] 生物化学/生物物理

[关键词] Fusion activity of HIV-2 envelope glycoprotein;HIV-1;human immunodeficiency virus type 1;HIV-2;human immunodeficiency virus type 2;DMEM;Dulbecco's modified Eagle's medium;D10;DMEM supplemented with 10% heat-inactivated fetal bovine serum;100 U/ml penicillin;100 μg/ml streptomycin;PBS;phosphate-buffered saline containing 137 mM NaCl;2.7 mM KCl;8.1 mM Na2HPO4;1.5 mM KH2PO4;pH 7.4;EBSS;Earle's balanced salt solution;EBSS−Ca2+;EBSS without calcium and magnesium;EBSS+Ca2+;EBSS supplemented with 1.8 mM calcium;CMTMR;(5-(and 6)-(((4-chloromethyl)benzoyl)amino)tetramethylrhodamine